classMain {
publicstaticvoidmain(String[] args) {
int n = 10;
System.out.println(n + isHappy(n)?"是":"不是" + "快乐数");
}
public boolean isHappy(int n) {
while(n >= 10){
int res = 0;
while(n > 0){
int val = n%10;
res += val * val;
n /= 10;
}
n = res;
}
return (n == 1 || n == 7);
}
}